The present invention relates to an anode device of an outboard motor having an improved anode mounting structure.
An outboard motor is provided with an engine having various metal portions or parts, such as cooling water passage, which contact the sea water (brine). Such metal portion may be dissolved into the sea water through the contact thereto and, hence, corrode. This is because the outboard motor is provided with various metal portions or parts formed of different materials, and according to such material difference, an electric potential difference will be caused therebetween. Particularly, a cylinder block of an engine includes a main portion formed of an aluminium alloy, which is liable to easily corrode in comparison with other portions.
In order to obviate such defect, in an actual structure of the outboard motor, a metal such as zinc (Zn) having a potential lower than that of the aluminium alloy is provided at a portion of the outboard motor contacting the sea water or positioned below the sea water level at a time when a hull mounted with the outboard motor is placed on the sea water, such metal being called "sacrifice metal or sacrifice anode" (hereinafter merely called "anode"), thereby preventing the metal portions such as cylinder block of the engine from corroding.
Such anode is mounted to a portion near a cooling water take-in port or a lower case which is disposed below the sea water level such as disclosed in Japanese Patent Laid-open Publication Nos. HEI 6-219387 and HEI 8-48289. Further, in recent years, there is provided a structure in which the anode is accommodated in a water jacket for cooling a cylinder formed to the cylinder block because the solubility of the anode is degraded at an occasion that the sea water surrounding the anode has a low temperature.
However, in an arrangement that the anode is accommodated in the water jacket for cooling the cylinder formed to the cylinder block, it is obliged to dismount the engine to remove a cylinder head every time for inspecting or exchanging the anode, providing a troublesome problem and requiring dismounting cost.
Furthermore, in the arrangement in the water jacket, there is a fear of disturbing or obstructing the flow of the cooling water.